1. Field of the Invention
The present invention generally involves the field of technology pertaining to a bed assembly defined by a mattress and a foundation. More particularly, the invention relates to an improved system for elevating or pivoting corresponding portions of a mattress and foundation.
2. Description of the Prior Art
The concept of providing a bed wherein portions of the bed may be bent at various angles for the purpose of conforming the support surface defined by the bed to different desired angular positions of the human body is well known. A bed of this type has heretofore found greatest utility in hospital or other institutional patient care facilities wherein the patient must spend a great deal of time in bed and therefore requires that the bed be adjustable in contour in order to accommodate different bodily positions during the waking hours. For example, it is desirable to at least elevate the head portion of the bed to permit the patient to read, watch television or partake of meals. It is further desirous to elevate or angle the lower portion of the bed for raising the legs of the patient for providing an angled support beneath the knees. The structural considerations required for the manufacture of beds of this type are quite complex and expensive to implement. Therefore, beds provided with elevatable or adjustable features have generally been confined to the medical and institutional markets rather than the retail consumer market.
The construction of a bed having at least an elevatable head portion requires several important considerations. First, the mattress must be provided with a suitable hinge construction which will permit pivoting of the head portion of the mattress to the desired elevated position without disturbing the otherwise uniform support afforded by the mattress, whether in its elevated or flat position. Second, the foundation must also be provided with an appropriate hinge construction which permits the corresponding head portion of the foundation to be jointly elevated with the head portion of the mattress in order to provide full underlying support for the mattress in both the elevated and flat positions. Third, the elevating of corresponding overlying portions of the mattress and foundation results in a foreshortening of the foundation due to the substantial thicknesses of the two members, thereby tending to cause the mattress to slide or shift out of its initial flat position of alignment on the foundation. This latter situation therefore requires that some means be provided for restraining the mattress in its position of alignment on the foundation. Fourth, the elevation procedure itself should be accomplished through a mechanism which is smooth, quiet and reliable in operation, and of sufficient compactness so as to be unobtrusively concealed within the foundation when it is not being utilized.
Some examples of prior art teachings believed to be representative of the state of the art with respect to various devices and mechanisms relating to elevatable bed structures and the aforediscussed considerations are disclosed by the U.S. Pat. Nos. 888,303 to Bowers, 1,384,600 to Coil, 1,559,119 to Miller, 3,099,843 to Simon, 3,135,971 to Haller and 3,520,030 to Hawkins.